http://auto.howstuffworks.com/question229.htm

http://www.mr2sc.com/websites/articles/vvt.htm

honda made the first production car to have variable valve timing, the 1991 NSX. but i'm pretty sure companies (not just honda) had been using it for years in racing. no idea who invented the concept

edit: VTEC and VVTi are a little different. VTEC = variable valve timing and lift electronic control. the links above should explain it. VVTi doesn't have lift. VVTLi probably does, i'm not sure. variable valve timing is pretty commonplace now, but for the past thirteen years it was almost uniquely honda.